[4Fe-4X]2+ (X = sulfur, selenium) clusters in Clostridium pasteurianum ferredoxin and in synthetic analogs: structural data from resonance Raman spectroscopy

Moulis, Jean‐Marc; Meyer, Jacques; Lutz, Marc

doi:10.1021/bi00321a050

Cited by 30 publications

(45 citation statements)

References 32 publications

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“…4 cm-l) upon 32+34S* substitution. This shift value confirms our measurement (5 cm-'; Moulis et al, 1984~) and strongly differs from the 2-cm-' value calculated from normal mode analysis of the model compound (Czernuszewicz et al, 1987). Moreover, the calculated value was obtained by assuming a no less than 40% contribution from bridging modes into this totally symmetric and formally terminal mode (Czernuszewicz et al, 1987).…”

Section: Discussionsupporting

confidence: 91%

“…Also, the presence of a similar group of bands in the spectra of both native and Se-substituted oxidized HiPIP between 370 and 435 cm-' (Figure 6) leads to their assignment mainly to FeScys stretchings, their higher apparent number in the case of native protein being probably due to the overlap of bridging modes in this region, as noticed at other redox levels (see above; Moulis et al, 1984c;Czernuszewicz et al, 1987). Although detailed assignments of the vibrational modes cannot be attempted with the present data, comparison of the RR spectra of both native and Se-substituted HiPIP indicates the occurrence of terminal modes in roughly the same frequency range but that of bridging modes for Se-HiPIP at lower wavenumbers than for S-HiPIP, as expected and already observed with ferredoxins (Moulis et al, 1984~).…”

Section: Resultssupporting

confidence: 79%

“…The spectrum of the selenium derivative is also very similar to the one observed with 2[4Fe-4Se] Cp Fd (Moulis et al, 1984b). Analysis of the latter has shown that most of the cluster modes are shifted to lower frequencies upon S/Se substitution, as expected from the replacement of an atom by a much heavier one (Moulis et al, 1984~). At ca.…”

Section: Resultssupporting

confidence: 65%

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Characterization of [4Fe-4Se]2+/3+ high-potential iron-sulfur protein from Chromatium vinosum

Moulis¹,

Lutz²,

Gaillard³

et al. 1988

Biochemistry

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Selenium atoms have been introduced into Chromatium vinosum high-potential ironsulfur protein (HiPIP) in place of inorganic sulfur at the [4Fe-4S] active site. The substitution induces a decrease of the redox potential by ca. 65 mV (from 350 to 285 mV vs N H E , 25 O C , p H 7.8) and results in changes of the optical and EPR spectra. Compared to the corresponding properties of native HiPIP, some of the charge-transfer transitions of the S e derivative shift to lower energies, and the almost axial S = EPR signal occurs at lower field with a larger anisotropy. As in the case of clostridial ferredoxins, the resonance Raman spectra of reduced HiPIP are very sensitive to S*/Se substitution. The bridging stretching modes of the inorganic core shift to lower frequencies upon replacement of S* by S e as expected, but the local D2d symmetry assumed by the active site remains. The availability of the Se derivative has further allowed us to define the vibrational properties of the oxidized cluster. The bridging modes are only marginally affected by electron removal, and thus, the relevant symmetry point group for the inorganic core is the same as at the reduced level (DZd). In contrast, the Fe-Scys stretching modes occur a t higher frequencies with larger splittings, implying that the major effect of oxidation is to strengthen and distort the Fe-Scys bonds. These data strongly suggest that one or two of the latter bonds play a crucial role in the electron exchange reaction between the active site and the redox partners of HiPIP.

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Section: Discussionsupporting

confidence: 91%

Section: Resultssupporting

confidence: 79%

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Characterization of [4Fe-4Se]2+/3+ high-potential iron-sulfur protein from Chromatium vinosum

Moulis¹,

Lutz²,

Gaillard³

et al. 1988

Biochemistry

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“…While such a high multiplicity spin system must arise from some kind of structural distortion, the latter is certainly not a significant structural rearrangement of the cubane clusters: indeed, the [4Fe-4Se] clusters of oxidized Cp Fd have been found to assume the same symmetry as the native clusters (Moulis et al, 1984b), and no degradation of the selenium-containing prosthetic groups has been evidenced upon reduction, neither in biochemical (Moulis & Meyer, 1982) nor in spectroscopic (Moulis et al, 1984a) investigations. It can therefore be concluded that the occurrence of the S = and S = 7 / 2 (Moulis et al, 1984a; this work) species in reduced selenium-substituted Cp Fd is a property of the [4Fe-4Se]+ clusters in this particular environment.…”

Section: Resultsmentioning

confidence: 99%

High-multiplicity spin states of 2[4Fe-4Se]+ clostridial ferredoxins

Gaillard¹,

Moulis²,

Auric³

et al. 1986

Biochemistry

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The electron paramagnetic resonance (EPR) spectra of the reduced selenium-substituted 2-[4Fe-4Se]+ ferredoxins from three bacteria of the Clostridium genus display low-field signals at g = 5.17, g = 10.11, and g = 12.76. The positions, shapes, and temperature dependencies of these signals have allowed their assignments to the three excited states of an S = 7/2 spin multiplet, the fundamental state of which is observed as unusual features in low-temperature (T less than or equal to 20 K) Mössbauer spectra. The S = 7/2 spin state is present in 2[4Fe-4Se]+ clostridial ferredoxins together with the classical S = 1/2 state and with a S = 3/2 state, the fundamental doublet of which is observed as a broad signal in the g = 3-4 region. The relative intensities of the EPR signals corresponding to these spin states depend on the species of Clostridium that the ferredoxin is extracted from. In contrast with clostridial ferredoxins, the reduced selenium-substituted ferredoxin from Bacillus stearothermophilus, which differs significantly from the clostridial proteins by its primary structure and by its containing only one tetranuclear cluster, displays only the S = 1/2 state. Thus, the high-multiplicity spin states arise from a specific interaction between the clostridial ferredoxin polypeptide chain and the reduced [4Fe-4Se]+ clusters.

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“…5) and assigned to S-Cys f Fe charge transfer bands (26). It should also be noted that the orientation (Fe-S-C-C and 1 dihedrals) of one cysteine ligand (Cys-40) is different for oxidized Cp and CvFd (10); this may change the CD features of cluster II, coordinated by Cys-40, and may explain the spectral differences between CpFd and CvFd, i.e.…”

Section: Redox Properties Of 2[4fe-4s] Proteinsmentioning

confidence: 99%

The Two [4Fe-4S] Clusters in Chromatium vinosumFerredoxin Have Largely Different Reduction Potentials

Kyritsis¹,

Hatzfeld²,

Link³

et al. 1998

Journal of Biological Chemistry

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[4Fe-4X]2+ (X = sulfur, selenium) clusters in Clostridium pasteurianum ferredoxin and in synthetic analogs: structural data from resonance Raman spectroscopy

Cited by 30 publications

References 32 publications

Characterization of [4Fe-4Se]2+/3+ high-potential iron-sulfur protein from Chromatium vinosum

Characterization of [4Fe-4Se]2+/3+ high-potential iron-sulfur protein from Chromatium vinosum

High-multiplicity spin states of 2[4Fe-4Se]+ clostridial ferredoxins

The Two [4Fe-4S] Clusters in Chromatium vinosumFerredoxin Have Largely Different Reduction Potentials

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